Microneedles have been in use in cosmetic treatments for collagen induction therapy for over a decade. More recently microneedles have been developed for drug delivery applications. The methods of applying the drug using microneedles include needles produced from drug that is inserted into the skin, solid needles coated with drug that dissolves in the skin, hollow needles with a bore via which drug is forced into the skin, creation of pores in the skin followed by application of drug on top of the skin/pores, and creation of pores followed by placement of drug directly above or into the skin.
Needles produced using fabrication techniques lend themselves to high needle densities. However it is often preferable to produce needles from stainless steel metal and other solids, from the point of view of tip sharpness and mechanical strength. These needles when assembled are generally of low density, as the density is restricted as a result of the proximity of needles and methods available to place them and secure them at such close proximities. It would be desirable therefore to attain a commercially viable process to produce high density needle arrays using individual solid or hollow needles.